- #1
Jay9313
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ρ
Oil with a density of 850 kg/m^3 is flowing at a velocity of 20 m/s at the atmospheric pressure in a horizontal tube elevated at 20m above the sea level. Please determine the diameter of the tube if the rate of mechanical energy for oil is 60000 J/s
dE/dt = \frac{ρv∏D<sup>2</sup>}{4} * (\frac{P}{ρ} + \frac{20<sup>2</sup>}{2} + 9.81 * 20) = 60,000
Now, my question is, P/ρ. I was told that it is at atmospheric pressure, but the pressure I use for that equation, is it absolute or gage?
EDIT: It's not coming out properly, I just need to know if the P in P/ρ is gage or absolute or should it matter? I did it both ways and got a diameter difference of about 20mm
Homework Statement
Oil with a density of 850 kg/m^3 is flowing at a velocity of 20 m/s at the atmospheric pressure in a horizontal tube elevated at 20m above the sea level. Please determine the diameter of the tube if the rate of mechanical energy for oil is 60000 J/s
Homework Equations
The Attempt at a Solution
dE/dt = \frac{ρv∏D<sup>2</sup>}{4} * (\frac{P}{ρ} + \frac{20<sup>2</sup>}{2} + 9.81 * 20) = 60,000
Now, my question is, P/ρ. I was told that it is at atmospheric pressure, but the pressure I use for that equation, is it absolute or gage?
EDIT: It's not coming out properly, I just need to know if the P in P/ρ is gage or absolute or should it matter? I did it both ways and got a diameter difference of about 20mm